RXM-900-HP-II Linx Technologies Inc, RXM-900-HP-II Datasheet - Page 9

• Manufacturer Part Number: RXM-900-HP-II
• Description: RECEIVER RF 900MHZ 8-CH PACK
• Manufacturer: Linx Technologies Inc

Specifications of RXM-900-HP-II

• Frequency: 902MHz ~ 928MHz
• Sensitivity: -95dBm
• Data Rate - Maximum: 50 kbps
• Modulation Or Protocol: FM, FSK
• Applications: Home / Industrial Automation, Remote Access, Security Alarms
• Current - Receiving: 18mA
• Data Interface: PCB, Through Hole
• Antenna Connector: Through Hole
• Voltage - Supply: 2.7 V ~ 16 V
• Operating Temperature: 0°C ~ 70°C
• Package / Case: 18-SIP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Features: -
• Memory Size: -
• Other names: RXM-900-HP2; RXM-900-HP2

POWER CONSIDERATIONS
POWER SUPPLY
POWER UP SEQUENCE
The user must provide a clean source of power to the receiver to ensure proper
operation. In an FM receiver, power-supply noise will manifest itself as AM and
FM noise in the receiver circuitry, reducing the
overall sensitivity of the receiver. Providing a
good power supply for the module is a
designer’s first line of defense in the battle for
receiver sensitivity.
The HP-II-RXM incorporates a precision Low-
Dropout Regulator on-board which allows the
module to operate over an input voltage range
of 2.7 to 16 volts DC. The module’s power-
supply line should have low ESR bypass
capacitors configured as shown in fig. 13.
The HP-II-RXM is controlled by an on-board microprocessor. When power is
applied, a start-up sequence is executed. At the end of the start-up sequence,
the receiver is ready to receive data.
Figure 14 shows the start-up sequence. This sequence is executed when power
is applied to the VCC pin or when the PDN pin is cycled from low to high.
On power-up, the microprocessor reads the
external channel-selection lines and sets the
frequency
channel. Once the frequency synthesizer has
locked on to the selected channel’s frequency,
the receiver is ready to accept data.
Figure 4 on Pg. 3 shows the typical turn-on
response time for an HP Series-II receiver. The
response time was measured by connecting the
module’s RF input to a signal generator which is
set to the proper channel frequency with an
output power of -80dBm and FM modulated at
50kHz deviation with a 1kHz square wave. You
will notice that the data output remains squelched
until the internal start-up procedure has been
executed and the receiver is ready to receive
data.
The HP-II-RXM can be put into an ultra-low-
current (<50uA) power-down mode by holding
the PDN pin low. If the PDN pin is left floating or
held high, the receiver will turn fully on. In power-
down mode, the receiver is completely shut
down. Thus, the RSSI circuit CANNOT be used to
monitor for channel activity.
synthesizer
to
the
appropriate
Figure 13: Suggested supply filter
Figure 14: Start-up sequence
V
cc
IN
Begins to Operate
Crystal Oscillator
Selection Inputs
Read Channel-
>22 F
Squelch Data
Synthesizer
POWER ON
Output Pin
Frequency
Main Loop
Program
Go To
module
V
cc
to
.1 F